He was accused of being an "old-fashioned shyster fraudster" and a "bare-faced liar" who created sham documents to "trick" a corruption inquiry.

Nick Di Girolamo, 44, the man who bequeathed the bottle of Penfolds Grange that brought down Barry O'Farrell, has been the subject of scrutiny at the Independent Commission Against Corruption.

The Liberal identity and former managing partner at law firm Colin Biggers & Paisley joined Rouse Hill Infrastructure Consortium as a director in 2005. The company's name was later changed to Australian Water Holdings.

It has been revealed Mr Di Girolamo gave himself a $1.1 million salary plus bonuses of $425,000 when he became chief executive and 60 per cent owner of Australian Water Holdings in February 2007. The salaries were billed back to Sydney Water.

Eddie Obeid junior, the youngest son of crooked former Labor minister Eddie Obeid and a good friend of Mr Di Girolamo, also joined the company in 2007.

The Obeid family paid Mr Di Girolamo $3 million for 30 per cent of AWH in November 2010, which they claimed was a loan.

The family stood to make $30 million to $60 million if they secured a public-private partnership with the NSW government.

The company also donated more than $43,000 to Mr O'Farrell's election campaign in 2010.

AWH only had 10 to 12 employees, including partner John Rippon, who owned a racehorse with Mr Di Girolamo named Partners in Crime.

In February, Mr Di Girolamo resigned as a director of the state-owned State Water Corporation after it was announced he was embroiled in a corruption inquiry. He has since fronted the ICAC, which heard the explosive evidence on Tuesday that he had sent Mr O'Farrell a $3000 bottle of 1959 Penfolds Grange Hermitage around April 20, 2011, after the Premier was elected.

While Mr O'Farrell said he could not "recall the receipt of a gift of a bottle of 1959 Grange," a thank you note from him to Mr Di Girolamo was tendered at ICAC on Wednesday morning. Shortly after, the Liberal leader resigned as Premier during a surprise press conference. The note was acquired by the ICAC via an email from Mr Di Girolamo's barrister.